Relay.



A. A. TIRRILL.

RELAY.

APPLICATION FILED 111111.27, 1908.

Patented June 30,1914.

2 SHEETS-SHEET 1.

A. A.`TIRR1LL. RELAY.

APPLIGATIUN FILED APR. 27, 1908.

1,1 01,670. Patented June '30, 191 2 SHEETS-SHEET 2 FCJ- Z lnvenor AHer) ATrriH.

Atis'y.

UNITED STATES PATENT OFFICE.

ALLEN A. TIRRILL, 0F SCI-IENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK. i

RELAY.

l Specification of Letters Patent.

Application led April 27, 1908. Serial No. 429,326.

Patented June 30, 1914.

T0 all whom, it may concern.'

Be it known that I, ALLEN A. TIRRILL, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Relays, of which the`following is a specification.

This invention relates to relays and particularly to an improved relay for use ,in the lso-termed Tirrill systems of voltage regulation.

As is well known, voltage regulators of the form shown in my Patent #726,234 operate by opening and closing a shunt around a resistor included in the shunt iield circuit of a generator. The action is automatic, being effected by one or more relays controlled by a main magnet which is responsive t0 changes in the line voltage and which con trols a pair of contacts in a derived circuit including the windings of the relays.

*The object of this present invention is to provide an improved relay which shall be capable of simultaneously opening and closing any number of shunt circuits, and the special construction by which this is accomplished forms the subject matter of this application. In brief, the relay has a circular winding, combined with a plurality of separatecores, each of which eoperates with its own armature and contacts to control a particular circuit. As these various contact-making armatures operate in unison, and each contact shunts by its closure a certain amount ofv resistance, it follows that a greater total amount of resistance can bei 1,.vis-a diagram of a system using a voltage regulator equipped with my improved relay;

Fig. 2 is a front elevation of the relay on a larger scale; and Fig. 3 is a radial sectional elevation of said relay.

In order that the application andoperation of my relay may be clear. I will first refer to Fig. 1 and later describe the actual construction as illustrated in Figs. 2 and 3.

Referring to Fig. l it will be seenthat it shows two threeephase alternating-current generators 3 4, feeding into bus bars 5, from which a load circuit 6 is led. The ield coils of these generators are supplied with direct current from the buses 7 which are fed by the eXciters 8, 9, 10. In series with the shunt field coils of each of these exciters is a resistor, numbered 11, 12, 13 respectively. Ashunt circuit 14 is connected around the resistor 11, containing a pair of contacts 15, which are shunted by a condenser 16. The resistor 12 is divided into two portions or sections, each of the same ohmic resistance, and each section is shunted by circuits 17, 18, respectively, each controlled by a pair of contact-s 19, 20, respectively. In the same way, the resistor 13 is divided into two equal sections, one of which is shunted by the circuit 21 and contacts 22, and the other by the circuit 23 and contacts 24. Each pair of contacts is shunted by a condenser I6. It is now in order to describe the relay of which these contacts form a part. It consists preferably of two diiferentially-wound coils 25 26 (Figs. 1 and 3) arrangedvone in front of the other as one looks at the relay. The permanently connected winding 27 in the coil 25 runs in` the opposite direction to the similar winding 28 in the coil 26, while the differential winding 29 in the coil 25 runs in the opposite direction to the differential winding 30 in the coil 26. The reason for this is apparent upon inspection of Fig. 3, which clearly shows the E-shaped core 31 applied to the two coils and receiving them between its legs, the middle pole or leg serving as a spacer for said coils. The op'osite directions ofthe windings insures tiie proper magnetization of this core so that its inner and outer poles will be of the same polarity and the opposite of that of the middle pole. By this arrangement I am able to get a maximum pull on each armature, for it will be clear that each pole of .the magnctized core will attract the armature relays. If the coils were wound in the same direction there would be no resultant pole at the center of the E-shaped core andthe middle projection would have no attracting eifect. An armature 32 is pivoted 1in a bracket 33 secured adjacent to the inneir...pole and `by ion this location of the pivot a long bearing is ailorded to prevent twisting of the armature.

A. lever arm 34 is secured to the armature and extends in behind the inner coil to a point where it can be attached to the inner end oit a spring which is adjustable as to tension by means of a screw 36 supported in a bracket 37 which is bolted to the core. The outer end of the armature carries a con tact stud which cooperates with a similar stud mounted on the outer end of a light spring 38 secured to a standard 39 securely mounted on the panel 1. The outer end of said standard is preferably slotted, to receive the screws 10 by means of whichthe spring 3S is attached to it; the slot affording a possibility of adjustment. A flexible conductor el runs from the, armature to a low stud l2 on the panel, and current can be led to the standard and this low stud by screws 'which pass through the panel and afford means for connecting` the terminals or' one of the shunt circuits 1e, 17, 18, 21 or 23.

As previously stated, any desired number oi cores and contacts can be applied to the coils; in the drawings I have shown five, symmetrically arranged around the coils, which are preferably annular'.l The various cores are spaced by a ring 43.

A conductor fill (Fig. 1) runs from the positive exciter bus bar 7 through a resistor to the windings 27 28, their other terminals being connected to the return conductor e6. A branch conductor L17rextends from the conductor le to the floating contact-s of the main control magnet and thence to the windings 29 30, whose other terminals are connected with the return conductor 16.

The main control magnet is shown in diagram in l.P ig. 1, the direct-current coil 48 being` connected across the conductors eiland' gl-6, through a resistor 4:9, the magnet being provided with the usual stop core 51 and the movable core 52. The lever 54 connected to said core 52 carries a contact 55 and is normally pulled down by the spring or springs 72 attached thereto. Opposite the magnet 48 is the alternating current magnet 56 which has a movable core 57 attached to a pivoted lever 5S suitably fulcrumed, and carrying a contact 60 which coperateswith the contact on the lever 5/1; the two constituting' the so-called floating main contacts. This magnet has a potential winding 61 connected by means of. a potential transformer (L to the alternating current bus bars It also has a compensating winding 63 which is shown connected to a current transformer G4 located in the load circuit 6. The compensating winding is adjustable by means of the dial switch 65, so that any degree of compensation can .be obtained, depending on the line requirevor springs 72 ments. In axial alinement with the alternating current magnet is a daslrpot 66.

The cycle of operations of a regulator equipped with my improved relay is as follows :HF irst, the shunt circuits across the exciter field rhecstats are opened by means of suitable switches 71, and these rheOStLtS are adjusted to a point that will reduce the alternating current voltage considerably below normal. From this the alternating control magnet will be weakened and its core will :fall and cause the contact to close upon the upper contact 55. The direct current magnet has been weakened simultaneously with the other, and the spring attached to its lever have pulled down said lever toward the lever of the alternating current magnet. The closure yolthese lioating contacts closes the circuit of the windings 29 30 of the relay, which oppose the permanently connected windings 27 2S, and this demagnetizes the relay cores, allowing their armatures to be released and permitting their springs 35 (Fig. 3) to close the relay contacts. Then, by closing the switches in the exciter shunt circuits, and thereby effecting a short-circuitingof the rheostats 11, 12, 13, the voltage of the exciters will immediately rise and cause a rise in the voltage of the generators 3 This will strengthen the control magnets, and when the voltage reaches the value for which they have been adjusted the main contacts 55 60 will open, thus breaking the circuit of one set of the relay windings and permitting` the permanently connected set-to magnetize the cores and open the relay contacts. This throws the full resistance of the resistors 11, 12, 13 into the field circuits of the exciter-s, which tends to lower the voltage again. This cycle of operations is continued at a high rate of speed, owing to the sensitiveness oi' the direct current control magnet; and the result is to maintain a steady exciter voltage which will be increased or diminished according to the dcmands of the system.

F rom the foregoing, it will be evident that I have herein disclosed an improved form of relaywhich is particularly adapted to use with a Tirrill regulator but whose ield of usefulness is by no means so limited.' My

arrangement is especially desirable where it y is necessary t0 operate a number of relays simultaneously and speedily and where space and cost are essential considerations. By the use of two coils arranged in parallel I have reduced the resistance of the relay and hence for use with a given supply voltage get an increased number of ampere turns and consequently an increased magneto motive force. By winding` those coils which are connected in parallel in opposite directions I get a resultant pole at the middle projection of the E-shaped core. This middle projection is therefore useful and aids in a'tr tracting the armature instead of being of no advantage magnetically as would be the case were the windings which are connected in parallel wound in the saine direction. By placing a plurality of cores on the superposed coils I get an exceedingly compact and inexpensive relay operating a plurality of contacts. By arranging these cores radially with the brackets for supporting the arma- "ures on the outer circumference I am able to lake these bracketswider and obtain a more rigid pivotingv of the armatures with less opportunity for lateral movement. By using a differential winding Iget a faster action with less danger of sticking due to residual magnetism. All these advantages contribute toward making my relay novel, efficient, and reliable.

I conceive that various modications of the exact arrangement herein described might be made which would be within the scope of my invention, and I accordingly do not wish to limlt myself to the construction shown, biit seek in the appended claims to cover all such modiications which are properly included in the scope of my invention.

Vhat I claim as new and desire to secure by Letters Patent of the United States, is

l. In a relay, an E-shaped core provided with two coils between its legs, ing oppositely wound and connected in parallel so that a resultant pole is produced at the middle leg of the core.

2. A relay comprising two circular coils spaced apart, each coil being made up of two reversely arranged windings, the windings of one coil being connected in parallel with the oppositely arranged windings of the other coil, and E-shaped cores applied to said windings. In witness whereof, I have hereunto set my hand this 24th day of April, 1908.

ALLEN A. TIRRILL.

Witnesses:

BENJAMIN B. HULL, HELEN ORroRD.

the Commissioner of Patents,

Washington, D. C.

the coils be- 

